Perkins 1106A-70T, Operation Manual, Page: 31 / 58

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Engine Valve Lash - Inspect/
Adjust
To prevent possible injury, do not use the starter
to turn the flywheel.
Hot engine components can cause burns. Allow
additional time for the engine to cool before meas-
uring valve clearance.
Illustration 29 g00939480
Cylinder and valve location
(A) Inlet valve
(B) Exhaust valve
If the valve lash requires adjustment several times in
a short period of time, excessive wear exists in a
different part of the engine. Find the problem and
make necessary repairs in order to prevent more
damage to the engine.
Not enough valve lash can be the cause of rapid wear
of the camshaft and valve lifters. Not enough valve
lash can indicate that the seats for the valves are
worn.
Valves become worn due to the following causes:
• Fuel injection nozzles that operate incorrectly
• Excessive dirt and oil are present on the filters for
the inlet air.
• Incorrect fuel settings on the fuel injection pump.
• The load capacity of the engine is frequently
exceeded.
Too much valve lash can cause broken valve stems,
springs, and spring retainers. Too much valve lash
can be an indication of the following problems:
• Worn camshaft and valve lifters
• Worn rocker arms
• Bent pushrods
• Broken socket on the upper end of a pushrod
• Loose adjustment screw for the valve lash
If the camshaft and valve lifters show rapid wear, look
for fuel in the lubrication oil or dirty lubrication oil as a
possible cause.
Valve Lash Check
An adjustment is NOT NECESSARY if the
measurement of the valve lash is in the acceptable
range. Check the valve lash while the engine is
stopped. The temperature of the engine does not
change the valve lash setting.
If the measurement is not within the acceptable
clearance, adjustment is necessary. Refer to “Valve
Lash Adjustment”.
Valve Lash Adjustment
Table 3
Inlet Valves Exhaust Valves
Valve Lash
0.35 mm
(0.014 inch)
0.45 mm
(0.018 inch)
TC Compression
Stroke
1-2-4 1-3-5
TC Exhaust Stroke (1)
3-5-6 2-4-6
Firing Order
1-5-3-6-2-4 (2)
(1) 360° from TC compression stroke
(2) The No. 1 Cylinder is at the front of the engine.
Illustration 30 g00323903
Setting the valve lash
(1) Adjustment screw
(2) Feeler gauge
1. Remove the valve mechanism cover. Refer to
Disassembly and Assembly, “Valve Mechanism
Cover - Remove” For the removal procedure.
UENR0617 31
Air Inlet and Exhaust System
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